Add comma, otherwise coffee compilation fails

with the following error:

    strophe.muc.coffee:11:1: error: unexpected INDENT
    _connection: null
    ^^

using coffeescript 1.6.3
Bugfix. Check if Form is defined.

If we don't use the dataforms plugin then the Form object is undefined,
resulting in an error.
Regenerated the Javascript using CoffeeScript 1.6.3
Add helpers.js function to expose previously global methods/attrs.

See "Breaking changes" section of v0.7.4 release notes.
http://docs.busterjs.org/en/latest/changelog/#v0-7-4
Replace BOSH service with the one from https://conversejs.org

Looks like the Tigase BOSH service is no longer available.

Also bumped timeout.